The reaction of disulfides and sulfides with alkylating agents, and with alkylthiolating agents, will be studied for the purpose of preparing alkylthiosulfonium ions RSSR2 as either isolable salts or as reactive intermediates. The scope and stereochemistry of rearrangement of allylic thiosulfonium ions will be investigated, and the utility of the products of thiolation of allylic sulfides and higher homologues as synthetic intermediates will be examined. Attempts will be made to interconvert dithiols (such as dihydrolipoic acid) to cyclic disulfides (lipoic acid) by way of thiosulfonium ions. Other reactions to be studied include thiolation of thioesters, alpha-alkylthiocarboxylates, 2-alkylthiobenzoates, vinyl sulfides and ketene thioketals. Thiolation of amines and alkylation of sulfenamides as routes to thioammonium ions RSNR3 will be investigated and the chemistry of thioammonium ions and related azasulfonium ions R2SNR2 will be explored. The overall objective of the investigation is to elucidate the fundamental chemistry of compounds with S-S, S-N and S-N bonds. The significance of the work lies in the possible involvement of these compounds in biological chemistry.